The present invention relates to a gasket having main and auxiliary grommets around a hole to be sealed.
In a gasket, a grommet is frequently used to seal around a hole. A wire ring may be installed between flanges of the grommet to provide surface pressure thereat when the grommet is tightened.
When the grommet is installed in a metal laminate gasket formed of a plurality of metal plates, the metal plates are formed to have beads to thereby provide surface pressures on and around the grommet. However, when the gasket is basically formed of a compressible material, such as mixture of fibers and binders, the grommet is simply installed around a hole with or without the wire ring, because it is difficult to provide means for providing surface pressure on the compressible material.
Therefore, in the gasket formed of the compressible material and the grommet, when the gasket is tightened, generally one surface pressure is formed at the grommet around the hole to be sealed. In this gasket, since the surface pressure is concentrated at one portion, high surface pressure is formed around the hole. If surface pressure is strong, engine parts around the hole may be deformed by the high surface pressure.
Therefore, it is desirable not to concentrate the surface pressure at one portion around a hole to be sealed. However, in the conventional gasket formed of the compressible material, there is no means to properly disperse the surface pressure around a hole to be sealed.
Accordingly, one object of the present invention is to provide a gasket formed a compressible material and a grommet, wherein the surface pressure for sealing around a hole is not concentrated at one area.
Another object of the invention is to provide a gasket as stated above, wherein the surface pressure is widely formed on the engine parts to prevent damage of the engine parts.
A further object of the invention is to provide a gasket as stated above, which can be easily and economically manufactured.
Further objects and advantages of the invention will be apparent from the following description of the invention.